In an additive three-dimensional fabrication system, a physical object can be realized from a digital model by depositing successive layers of a build material that accumulate to provide the desired form. Certain additive techniques render each layer as a single, continuous path of an extruded material, typically completing a layer of the object in an x-y plane and then stepping to a next z position (or height) for each subsequent cross-sectional plane, all under computer control.
Techniques such as partial stepping or micro-step driving have been devised to increase spatial resolution for stepper motors typically used to control x-y positioning in such additive techniques. However, there remains a need for additive fabrication techniques that permit independent application of surface texture and other surface features, in particular small or sub-pixel features, to a model during fabrication.